Effects of gabapentin on intraocular pressure, tear production and horizontal pupil diameter in New Zealand White rabbits.

BACKGROUND: This study aimed to investigate the effects of gabapentin on various ocular parameters in New Zealand White rabbits. METHODS: A randomised, placebo-controlled crossover study design was employed. Eight New Zealand White rabbits were randomly assigned to receive either oral gabapentin at a dosage of 15 mg/kg or an oral placebo, with a 1-week washout period between treatments. Intraocular pressure, tear production and horizontal pupil diameter were measured at baseline (T0) and at 30, 60, 90, 120, 180, 240 and 360 minutes after drug administration. Physiological and behavioural changes were also recorded for both treatments following drug administration. RESULTS: The administration of gabapentin did not have any significant effects on the ocular parameters measured in this study. However, the rabbits exhibited some muscle relaxation with partially closed eyes during handling, and they were slightly easier to remove from the cage when treated with gabapentin compared to the placebo treatment. LIMITATIONS: In this study, the ocular effects of gabapentin were assessed in only a small number of healthy rabbits. These effects may differ in rabbits with pre-existing eye conditions or in those receiving other medications. CONCLUSIONS: Our findings suggest that gabapentin treatment does not have a significant impact on intraocular pressure, tear production or horizontal pupil diameter in rabbits.

Effects of intramuscular and intranasal administration of midazolam-dexmedetomidine on sedation and some cardiopulmonary variables in New Zealand White rabbits.

OBJECTIVE: To compare the sedative and cardiopulmonary effects of intranasal (IN) and intramuscular (IM) administration of dexmedetomidine and midazolam combination in New Zealand White rabbits. STUDY DESIGN: A randomized, crossover experimental study. ANIMALS: A total of eight healthy New Zealand White rabbits, aged 6-12 months, weighing 3.1 ± 0.3 kg (mean ± standard deviation). METHODS: The animals were randomly assigned to administration of dexmedetomidine (0.1 mg kg-1) with midazolam (2 mg kg-1) by either IN or IM route separated by 2 weeks. The electrocardiogram, pulse rate (PR), peripheral haemoglobin oxygen saturation (SpO2), mean noninvasive arterial pressure (MAP), respiratory frequency (fR) and rectal temperature were measured before drug administration (baseline), T0 (onset of sedation) and at 5 minute intervals until recovery. The onset of sedation, duration of sedation and sedation score (SS) were also recorded. RESULTS: The PR was significantly lower in treatment IM than in treatment IN over time (p = 0.027). MAP < 60 mmHg developed in two and four rabbits in treatments IN and IM, respectively. SpO2 progressively decreased over time in both treatments. fR was lower than baseline at several time points in both treatments. Onset of sedation was shorter in treatment IN (90 ± 21 seconds) than in treatment IM (300 ± 68 seconds) (p = 0.036). Duration of sedation was longer in treatment IM (55.2 ± 8.7 minutes) than in treatment IN (39.6 ± 2.1 minutes) (p = 0.047). No significant difference in SS was observed between treatments (p > 0.05). CONCLUSIONS AND CLINICAL RELEVANCE: Combination of dexmedetomidine (0.1 mg kg-1) and midazolam (2 mg kg-1) decreased fR, PR and SpO2 regardless of the administration route in New Zealand White rabbits. A more rapid action and shorter duration of sedation were observed after treatment IN than after treatment IM administration.